Degradation products plasticizing matrix

Kinetic Model for Starch Digestion and Product Release. Before the comprehensive mathematical model could be constructed, some assumptions were made from prior research on polymer degradation (10) (a) the diffusion of both the enzyme and the products in the plastic matrix obeyed Pick s first law, (b) the... 

Crystalline starch beads can be used as a natural filler in traditional plastics [3]. They have been particularly used in polyolefins. When blended with starch beads, polyethylene films biodeteriorate upon exposure to a soil environment. The microbial consumption of the starch component leads to increased porosity, void formation, and loss of integrity of the plastic matrix. Generally, starch is added at fairly low concentrations (6-15 wt%). The total disintegration of these materials is obtained using transition metal compounds, soluble in the thermoplastic matrix, used as pro-oxidant additives to catalyze the photo and thermo-oxidative processes [4]. These products belong to the first generation of degradable polymers that biodeteriorate more than mineralize to CO2 and H2O in a time... 

Other variables investigated with respect to fracture toughness include processing parameters, e.g.. production schedules and postcure cycles [166.171] for thermosets, and cooling rates for thermoplastics [171] matrix composites, and moisture content. A study [171] on composites based on epoxy and vinyl ester matrices has shown that whilst matrix plasticization improves mode I fracture toughness, mode II fracture toughnc.ss deteriorates due to interface degradation. The sensitivity of (Jut to water absorption has been demonstrated even for matrices that absorb very small amounts of water such as pol propy lene [168]. 

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